import java.util.Scanner;

public class Example9 {
    public static void main(String[] args) {
        //int grade =75;
        Scanner scl=new Scanner(System.in);
        int grade= scl.nextInt();
        if (grade>80){
            System.out.println("该成绩的等级为优");
        }else if(grade>70){
            System.out.println("该成绩的等级为良");
        }else if( grade>60){
            System.out.println("该成绩的等级为中");
        }else{
            System.out.println("该成绩的等级为差");
        }
    }
}
